The present invention relates generally to diagnostic radiology and, more particularly, to a system for producing radiographs of surgically biopsied tissue specimens.
Diagnostic radiology procedures often show a tissue abnormality which can only be identified as either malignant or benign by surgical biopsy and subsequent microscopic study. This is most often the case with mammography, the examination of the breast with radiography, where a suspected soft tissue tumor or an abnormal calcification seen on a mammogram frequently is not palpable due to its small size.
Accordingly, the tissue area containing the possible cancer must be localized preoperatively using a well-known needle/guidewire placement technique. The surgeon, guided by an implanted guidewire, removes a block of tissue thought to contain the abnormality. The tissue block is then examined by specimen radiography to determine if it does in fact contain the suspicious tissue. If the radiologist does identify the same abnormal tissue features seen during the initial radiological examination, the surgical portion of the procedure is concluded.
The abnormal tissue, which is frequently less than a centimeter in diameter, must then be localized within the larger tissue block, which usually ranges between 6 to 10 cm in diameter. Typically, the pathologist responsible for performing the microscopic examination of the abnormality cannot accurately identify it either by feel or by grogs tissue sectioning. Thus, the radiologist must assist the pathologist by precisely describing the area within the tissue block where the abnormality is located. Once the abnormality has been accurately localized, the pathologist excises a segment measuring 10 to 15 mm in diameter for fixation, sectioning, staining and microscopic examination.
In the past, it has been common practice to examine the tissue block while the block is placed on a radiographically visible grid. This practice presents a number of drawbacks, however. First, the superimposed shadow cast by the grid may obscure fine radiographic detail in the tissue block. This could cause the radiologist to mis-identify or fail completely to identify the location of the abnormality within the block.
Second, radiologists, lab technicians and other health-care workers find it difficult to handle and radiograph tissue specimens and, at the same time, prevent personal exposure to tissue fluids and equipment contamination. This is of particular concern in view of a recent program instituted by the Occupational Safety and Health Administration (OSHA) to enforce safety standards intended to limit occupational exposure to body tissues, blood and other tissue fluids.
Pursuant to these standards, every employer is required to anticipate and identify any such exposure in the workplace and provide protective equipment, an exposure control plan, appropriate safety devices and an employee educational program. Further, all body fluids and tissues from all patients must be treated as potentially lethal. At a minimum these so-called "universal precautions" will require gloves, gowns, masks, face shields and safe needle and tissue fluid disposal when conducting tissue specimen radiography.
It is, therefore, an object of the invention to provide a system for specimen radiography wherein the location of an abnormality within a tissue block can be easily and precisely identified.
It is a further object of the invention to provide such a system wherein fine radiographic detail within the tissue block is left completely unobscured.
It is a still further object of the invention to provide a system wherein a tissue specimen can be transported, manipulated and examined radiographically and by ultrasound without the risk of exposing health-care workers to potentially hazardous tissue fluids or contaminating equipment with such fluids.